alchohol?

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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BC Pneumatics
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Wed Jun 04, 2008 7:46 pm

Bigbob, I never said it was impossible to make, just that you cannot distill it. At a certain temp, both the water and alcohol are evaporating together. This means you cannot get any further through distillation. You can still 'dry' the alcohol to 100% by following any of a number of methods.
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daxspudder
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Wed Jun 04, 2008 9:38 pm

the atmospheric absorption of moisture by alcohol is off set by the cap on the bottle, which keeps atmosphere out and an accurate % of alcohol in. Walmart doesnt sell alcohol in excess of 90%, but CVS and RiteAid both sell 99%+. I have used a soaked cotton ball to swab alcohol onto my chamber fan, which when closed off and the fan immediately turned on, had a very very successful result, comparable to propane, except when I opened my clean-out cap (fan off) the gun dry fired itself since the alcohol remained lit. I havent used alcohol since.
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Wed Jun 04, 2008 9:52 pm

when I opened my clean-out cap (fan off) the gun dry fired itself since the alcohol remained lit.
Which brings up a thought. In a metal chamber it would be quite possible to heat and vaporize the alcohol prior to ignition. That would solve the after burning problem and most likely boost power(better fuel air mix).
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Wed Jun 04, 2008 10:02 pm

daxspudder wrote:the atmospheric absorption of moisture by alcohol is off set by the cap on the bottle, which keeps atmosphere out and an accurate % of alcohol in. Walmart doesnt sell alcohol in excess of 90%, but CVS and RiteAid both sell 99%+. I have used a soaked cotton ball to swab alcohol onto my chamber fan, which when closed off and the fan immediately turned on, had a very very successful result, comparable to propane, except when I opened my clean-out cap (fan off) the gun dry fired itself since the alcohol remained lit. I havent used alcohol since.
I got my 99% bottle from walmart...

Offtopic: OH! I finally finish building my newest cannon, a 6.5ft long, Sch. 40 ABS combustion. cant wait to try it out.
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magnum9987
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Thu Jun 05, 2008 4:07 pm

Well, to elliminate the remaining in the chamber after combustion, you could go make it a hybrid. By increasing air content or change the ratio of air/fuel to favor air more, you could burn all the alcohol in your single blast, making it more powerful.
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magnum9987
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Sat Jun 07, 2008 11:31 am

Update:
While looking at the label on cvs brand 70% Isopropyl rubbing alcohol
the ingrediants are as follows:
Blue 1
glycerin
methyl salicate
water
yellow 5

Notice ingrediant 2: Glycerin
I think this would give this stuff a little umf
http://www.spudfiles.com/forums/viewtop ... Revolution in the absolute is not initiated by swords, guns, and bullets, but by words-
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Sat Jun 07, 2008 11:52 am

Glycerin isn't going to do anything more than using a bit of oil or something in your fuel would. It is not very flammable, and will not release ton of energy. Just because replacing glycerine's hydroxide groups with nitrates makes a high explosive, does not mean glycerin is for some reason a good spudding fuel additive.
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magnum9987
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Tue Jun 10, 2008 3:06 pm

tiny drop of nitric acid? tiny tiny? the power would allow for an explosive compression of air and the gases. so for the tiny bit you get quite a bang.
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Tue Jun 10, 2008 3:25 pm

Sorry, no.
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magnum9987
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Tue Jun 10, 2008 3:29 pm

why not? It sounds like it is worth a try.
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Tue Jun 10, 2008 3:34 pm

If you do not know why it is a terribly idea, then you do not know enough about what you are talking about doing to do it safely. Yay, the problem solves it's self.
(Sorry, but it's true.)
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magnum9987
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Tue Jun 10, 2008 3:39 pm

care to elaborate? I just may try it. The next day you'll open a newspaper to find that I blew myself up. The you'll feel guilty not warning me and jump off a tall building. (Don't worry I'm not exactly, retarded.)
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Tue Jun 10, 2008 4:01 pm

magnum9987 wrote:care to elaborate? I just may try it.
Try this for an explanation.

Imagine you have a small pipette of Nitrogyclerine, and hold it out at arm's length, and squeeze out one drop onto a concrete surface.
That one drop would explode on hitting the ground, blow a hole larger than a house brick out of the ground, and the blast would set off the remaining stuff in the pipette, which would turn you into nothing more than bloody chunks of flesh.

When you make the stuff, it has to be kept below freezing point to avoid it being set off by it's own heat, and it can be set off by little more than a harsh glance - and when it goes off, there are few more powerful explosives known to man.

This is not stuff you mess with. Don't even think for a microsecond about trying it.
Does that thing kinda look like a big cat to you?
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magnum9987
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Tue Jun 10, 2008 4:08 pm

You hyperbole its sensitivity. I do know for a fact that it is a high explosive, and I do know it is sensitive. But, diffused into the alcohol, it would lose its strength, plus The precise ratio of glycerin/nitric acid would not be met, so, the nitroglycerin's full potential is not met.
http://www.spudfiles.com/forums/viewtop ... Revolution in the absolute is not initiated by swords, guns, and bullets, but by words-
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Ragnarok
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Tue Jun 10, 2008 4:18 pm

Well, of course a harsh glare won't set it off, but it is sensitive.

I've made the mistake of thinking that "explosives in small quantities are safe" - and that wasn't with anything even an order of magnitude close to nitroglycerine in peril.

Ever heard of the Darwin Awards? They're awards given to people who kill themselves through their own extreme stupidity.
If you don't heed the warnings you're being given, you're well on the way to winning one.
Does that thing kinda look like a big cat to you?
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